84 lines
2.1 KiB
C
84 lines
2.1 KiB
C
/*-------------------------------------------------------------------------
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_gptrget.c :- get value for a generic pointer
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Written By - Sandeep Dutta . sandeep.dutta@usa.net (1999)
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This library is free software; you can redistribute it and/or modify it
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under the terms of the GNU Library General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this program; if not, write to the Free Software
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Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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In other words, you are welcome to use, share and improve this program.
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You are forbidden to forbid anyone else to use, share and improve
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what you give them. Help stamp out software-hoarding!
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-------------------------------------------------------------------------*/
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unsigned char _gptrget ()
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{
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_asm
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; save values passed
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xch a,r0
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push acc
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;
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; depending on the pointer type
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;
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mov a,b
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jz 00001$
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dec a
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jz 00002$
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dec a
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jz 00003$
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dec a
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jz 00004$
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;
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; any other value for type
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; return xFF
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mov a,#0xff
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sjmp 00005$
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;
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; Pointer to data space
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;
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00001$:
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mov r0,dpl ; use only low order address
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mov a,@r0
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sjmp 00005$
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;
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; pointer to xternal data
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;
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00002$:
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movx a,@dptr
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sjmp 00005$
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;
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; pointer to code area
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;
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00003$:
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clr a
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movc a,@a+dptr
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sjmp 00005$
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;
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; pointer to xternal stack
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;
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00004$:
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mov r0,dpl
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movx a,@r0
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;
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; restore and return
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;
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00005$:
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mov r0,a
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pop acc
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xch a,r0
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_endasm ;
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}
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